Continuous plating system

ABSTRACT

An exit conveyor for continuously removing articles from a container. A longitudinally extending conveyor trough having a sawtoothed floor is angularly disposed in said container with its lowermost end positioned to receive articles to be removed and its uppermost end positioned to discharge the articles. The conveyor trough is cyclically driven rapidly forwardly and upwardly to transport articles in said trough forward and upward, and then abruptly rearwardly and downwardly to momentarily suspend said articles above said trough. The trough is then held for a predetermined dwell period to permit inertial deposition of the suspended articles forward and upward of their original position.

United States Patent 1191 Faust July 30, 1974 [54] CONTINUOUS PLATINGSYSTEM 1,456,389 /1923 Linkowski 198/220 DA 2,062,760 12/1936 Overstrom209/415 X [75] lnvemor- Elbe" Falstr Lltchfieldl Com 2,214,755 9/1940Tafel 198/220 DA [73] Assignee: The Buehler Corporation,

Indianapoli Ind, Primary Examiner-Edward A. Sroka Filed J 29 1972Attorney, Agent, or Firm-Trask, Jenkins & Hanley 9 [21] App1. No.:267,408 [57] ABSTRACT Related US Application Data An exit conveyor forcontinuously removing articles [60] Division of Scr. N0. 120 635 March 31971 Pat. from a m A longitudinally. extending cqnveyor No. 3,699,985,which is a continuation-impart of Ser. g havmg a Y Q floor angularly,dlsposed 796033, Feb 3' 1969 p 3,616,421 1n said contalner with itslowermost end pos1tioned to l 5 receive articles to be removed and itsuppermost end 52 US. Cl. 198/220 BA Pcsilicncd to discharge thcarticlcs- Thc ccnvcycr 51 1m. 01. B65g 15/42 trcugh is cyclically drivenp y forwardly and p- 58] Field of Search 198/220 BA, 220 CA, wardly totransport articles in said trough forward and 220 DA; 209/365 B,4l5,462;143/ 160 pward, and then abruptly rearwardly and downwardly tomomentarily suspend said articles above 5 References Cited said trough.The trough is then held for a predeter- UNITED STATES PATENTS mineddwell period to permit inertial deposition of the suspended articlesforward and upward of their origi- 218,757 8/1879 Martin 198/220 DA Xnal position 629,466 7/1899 Quackenbush /462 X 757.477 4/1904 Marcus198/220 BA 5 Claims, 12 Drawing Figures o 80 [7:08 84 9 4 7 a a, 7 I, 7a73 5 7a b 7 66 77 7/ I 59 I at 6 6/ 65 I 4 65*? 20 38 67 65 c N NW 86 I?Y /06 in, h q 64 rd t 1 E 11 1| 6 0 "45* 4 1 09 W 82 TK77 PAIENTEB I3.826.355

SHEET 3 OF 4 FIG. 7 I

F/G.8 I 1 9 CONTINUOUS PLATING SYSTEM This application is a division ofco-pending application Ser. No. 120,635, filed Mar. 3, l97 l now U.S.Pat. No. 3,699,985, which is in turn a continuation-in-part ofapplication Ser. No. 796,033, filed Feb. 3, 1969, now U.S. Pat. No.3,616,423, issued Oct. 26, 1971.

- FIELD OF THE INVENTION This invention relates to-electroplatingsystems and more particularly to systems especially useful for thecontinuous plating, cleaning and rinsing of small articles.

BACKGROUND or THE INVENTION Articles to be electroplated areconventionally processed on a batch basis. In one well knownelectroplating system, items to be plated are loaded into a basket whichis transported by means of an elaborate manually or automaticallycontrolled conveyor mechanism through the necessary cleaning, platingand rinsing baths. In another known plating system, items are loadedinto a rotatable barrel which is then lowered into a plating solutionand rotated therein to plate the items contained within the barrel.These plating systems are rather complex and, since they operate on abatch-by-batch basis, are limited in the speed with which plating can beeffected. The inherent slowness of these conventional systems, togetherwith the additional labor required in loading and unloading items beingprocessed, increases the cost of plating and correspondingly adds to thecost of articles so plated. Moreover, it is often difficult by suchconventional techniques and systems to provide a complete and uniformcoating on articles, especially on relatively small articles such aselectronic components. In addition, conventional systems can oftendamage or tangle items being processed since the items are usuallytumbled or agitated to provide uniform coating.

SUMMARY OF THE INVENTION In accordance with the present invention, acontinuous electroplating system is provided wherein small articles areefficiently, uniformly and entirely plated by apparatus which isrelatively simple and yet especially adapted for high volume continuousproduction plating. The system comprises a novel and particularlyeffective conveyor assembly operative to transport items to be plated inan essentially continuous manner through a plating bath and in a mannerwhich achieves uniform coating with substantially no damage to theitems. A trough is suspended or mounted within-a plating bath and isoperative to cyclically move forward and upward in a smooth manner andabruptly return to an initial or rest position such that items'restingwithin the trough are carried-forward and upward during the smoothmovement of the trough without changing position, and as the troughabruptly returns to its rest position, the items are caused toi'nertially fall to new posithe bath by similar periodic motion and aredeposited onto suitable conveyor means for transport out of the platingsolution and into subsequent cleaning or rinsing baths, as required in aparticular process.

The trough is generally fabricated of an electrically insulativematerial compatible with the plating solution employed and has anelectrode structure provided in the floor thereof which is constructedto suit particular process requirements. The novel system operationpermits relatively simple replenishment of plating fluid, and permitsefficient arrangement of electrodes within the plating bath-Theinvention can also be employed in cleaning and rinsing baths of anelectroplating system to uniformly process the items, and is usefulgenerally for the processing of items where uniform and completeexposure to an immersing fluid, which can be liquid or gas, 'is desired.1

DESCRIPTION OF THE DRAWINGS The invention will be more fully understoodfrom the following detailed description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a diagrammatic elevation view of a plating system according tothe invention;

FIG. 2 is a sectional end view of the plating syste of FIG. 1;

FIG. 3 is a sectional cut-away view of an alternative embodiment of thetrough of FIG; 1';

FIG. 4 is a diagrammatic elevational view of a modified form of theplating system shown in FIG. 1, and including mechanical aspects ofapparatus embodying and for practicing this invention;

FIG. 5 is a view in cross-section taken along lines 5--5 of FIG. 4; t

FIG. 6 is a sectional view of a portion of the trough of FIG. 4 andgiving a detailed showing of the configuration of perforationsin thetrough floor;

FIG. 7 is a cross-sectional view of the plating system of .FIG. 1 takenalong lines 7--7 of FIG. 1;

FIG. 8 is a detailed showing of one arrangement of the flexiblesupporting struts shown in FIG. 1;

FIG. 9 is a longitudinal sectional view of the trough floor showing amodified arrangement thereof and including mechanical aspects ofapparatus embodying and for practicing this invention;

FIG. 10 is a cross-sectional view of the trough floor of FIG. 9;

FIG. 11 is a somewhat diagrammatic view in elevation of one arrangementof a control for the apparatus of FIG. 4; and

FIG. 12 is a side elevational view of the control of FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION I A plating system especiallyuseful for the continuous plating of small articles is illustrated inFIG. 1 and comprises a plating tank 10 containing a suitable platingsolution, a trough conveyor 12 pivotally mounted within the platingbath, supply means 14 for directing items to be plated into the trough,and conveyor means 16 operative to remove plated items from the bath.Trough conveyor 12 includes an elongated trough of channel- -shapedcross-section formed of an electrically insulative material, typicallyplastic, which is compatible with the fluid in which it is immersed. Thetrough 18 is disposed below the surface of the plating solution andarranged for motion within the plating tank along the longitudinal axisthereof. Trough 18 is pivotally supported by hangers 20 and 22 disposednear respective opposite ends thereof, the hangers being pivotallyattached at their lower ends to trough 18 and pivotally attached attheir upper ends to a rigid support 24. The trough is thus'supported bya parallel suspension system which allows pivotal parallel motionthereof; in other words, longitudinally and upwardly motion parallel tothe plating bath surface.

A supply pipe 26 is disposed within the. plating bath with its orificeor orifices oriented centrally of trough 18 to provide a controlled flowthrough or into the trough to suit particular process requirements. Aconductive rod or plate 28 disposed in the bottom surface of trough .18servesvas the cathode electrode while an elongated perforated member 30,or basket, disposed within or above trough 18 serves as the anodeelectrode. Other well known electrode configurations, such as anodehangers or danglers can also be employed. Electrical connection is madefrom cathode 28 to cathode bus bar 32 by means of a cable 3.4 whichextends from bus. bar 32 through hanger 20 to cathode plate 28.Electrical connection is made to the anode fromanode bus bar 36 by meansof a rigid conductive member 38 which can also serve tophysicallysupport anode 30 in its position within the trough 18. Conductive member38 can of course be electrically insulated to reduce shock hazard.

Motion is-imparted to the trough conveyor assembly by means of a cam 40which is rotatably driven in a clockwise direction by suitable motivemeans, the cam operating with a cam follower 42, attached to or formedas part of hanger 22, in a manner to provide the novel plating operationaccording to the principles of the invention. The motive means can beelectrical, hydraulic or pneumatic. A spring 44 attached betweenasupport 46 and hanger 20 urges trough 18 and its associated suspensionassembly into positive contact with the camming surface of cam 40.Alternatively, two cams or a two lobed cam may be used, in place of thesingle cam and spring illustrated, to provide the requisite forward andrearward trough motion. in some instances, return of the trough can besimply via gravity, and motion in either direction can be accelerativeto achieve particular trough movement. a

- According to the invention, the trough conveyor assembly 12 iseffective to transport items being plated through the plating solutionin an effectively continuous manner by use of unique periodic movementwhich achieves uniform and complete plating. The unique periodicmovement of the items being plated is accomplished by trough 18 which iscaused to move longitudinally and upwardly in a first direction, therebyto longitudinally and upwardly transport items within the trough, andcaused to move abruptly in an opposite direction, rapidly returning thetrough to a rest position whereupon the items are momentarily suspendedwithin the plating solution and are caused to fall onto the bottomsurface of the trough in a position forward of their former position.The trough motion continues sequentially to increment-the items alongthe trough,

in FIG. 1 by an arrow, causing trough 18 to move leftwardly and upwardlyas seen in FIG. 1 as cam surface 48 cooperates with follower 42. Whencam follower 42 reaches the abrupt discontinuity in camming surface 48,trough 18 is rapidly returned to the rest position, as illustrated, bythe urging of spring 44 to provide the necessary abrupt return motion ofthe trough. The extent of trough movement is determined by theparticular characteristics and location of cam 40 in conjunction withthe dimensions of the hanger supports, while the frequency of troughmotion is determined by the speed of rotation of cam 40. Particulardegrees of trough motion and frequency can be determined to suit therequirements of specific plating operations. It should be understood,however, that themovement, in accordance herewith, is not vibratory innature, but rather sequential with momentary periods of rest during theactual plating portion of the sequence and at the uppermost-point ofmovement in accordance with the particular plating demands.

The periodic trough motion lends itself to interruption of platingcurrent during portions ofv the periodic cycle. Plating occursessentially during the time when the items are in contact with thecathode disposed the trough, that is, during forward motion of thetrough. To conserve power, or to modify the plating process, current canbe switched off during return movement of the trough when the items arecaused to fall through the bath to their reoriented positions forwardlyof the trough. Such current interruption can be accomplished by asuitable switch activated by the trough conveyor, for example, by thecam 40 or one of the hangers 20 and 22. Suitable means may be used tohalt the trough motion to increase or decrease the duration of theplating cycle. i

In operation of the device as shown in FIG. 1, items to be plated arecontained within supply bin 14 and are delivered by means of a chute 50to the supply end of trough 18. Items can be fed from the supply bin tothe plating bath, for example, by means of a well known vibratory feedmechanism contained within bin 14. The items are deposited at the supplyend of trough 18 in a random manner and these items are conveyed throughthe plating solution by the novel motion of trough 18, th items beingperiodically deposited by the cyclic action of trough 18 on successivelyleftward po sitions of the trough. The items experience sufficienttrough 18 are transported by the same periodic movement onto conveyor 16by which the plated items are removed from the plating bath. The itemsmay then be transported by suitable conveyor means to subsequent bathsfor further plating operations or for cleaning or rinsing. Subsequentoperations can be conducted by the items moving generally in a periodicfashion so that systems substantially similar to that describedhereinabove, as can preplating operations such as degreasing.

Variations in the particular implementationofthe invention can be madeto suit process requirements. For example,'the trough bottom can beconfigured to aid the orientation of articles as they fall thereon byvirtue of the uniqueperiodic trough motion. One such contigured troughis illustrated in H6. 3 and includes a plurality of inclined surfaces 60arranged across the width of the trough and inclined longitudinallythereof, and appearing in the illustrated longitudinal section as asaw-tooth pattern. As a trough with this configured bottom surface movesabruptly to its rest position (to the right in the figure) items beingconveyed fall onto the inclined surfaces and tend to tumble downwardlyof the inclines. Normal arrangements of individual trough sections orlevels, however, will perferably be parallel to the liquid surface.Rearward inclination is used to increase plating time, whereforward'inclination is used to accelerate forward movement and decreaseplating time. Acceleration in the downward and, rearward direction mayalso be used to increase the tumbling actron.

Thus, reorientatin of items during their path through the bath isachieved to permit plating of all item surfaces. In some instances, thecathode electrode is preferably non-continuous and such cathode can beimplemented in the invention by providing discrete conductive areasalong th length of the trough bottom.

Tandem or cascade operation can be provided by use of multiple troughs,mounted for motion as described hereinabove, and the trough can bepartitioned along the length to provide, in effect, separate troughsuseful, for example, in processing articles which tend to nest or becomeentangled.

Modifications in the trough suspension and conveyor assemblies can alsobe made. For example, in place of the parallel suspension describedhe'reinabove, a plurality of resilient members attached to or formed aspart of the trough can be employed to support the trough and permitrequisite motion. The resilient supports can be of a plastic materialsuitable to allow the necessary bending required to achieve the uniqueperiodic trough motion, and offer the advantage of eliminating bearingsor pivots within the bath.

FIG. 4 is a side elevational view of the plating system of FIG. 1 inwhich the suspension system and the means for moving trough 18 have beenmodified and with the direction of movement reversed with work piecesmoving from left to right. For example, disposed immediately abovetrough 18 is a movable frame 61 which is rigidly connected to trough 18as by spaced apart struts 20. Thus, the trough 18 and the movable framemove together cyclically in a first direction longitudinally andupwardly within tank and abruptly returning to the initial position.Movable frame 61 is supported on two pairs of spaced apart uprightsupports 71 and 72 disposed on either side of the edge of tank 10.Connection is made between the upright supports 71 and 72 and movableframe 61 as through two pairs of spaced apart flexible struts 62 and 63,which may be comprised of any flexible material appropriate for the sizeand design requirements of the apparatus. Flexible steel struts ornon-metallic flexible material such as fiber glass, for example, haveproved appropriate. It should be understood that the number of strutsmay be increased or decreased depending upon the size of trough 18 andthe load requirements of a particular plating operation.

These flexible struts are connected to movable frame 61 by pairs ofspaced apart clamps'64 and 65 which hold the lower ends of the flexiblestruts 62 and 63 rigidly in place. A similar two pairs of spaced apartclamps 66 and 69 are rotatably disposed on cross bars 73 extendingbetween the uprights 71 and 72 on the tank edges. Thus, the movableframe with the trough 18 depending therefrom is supported for movementas through the two pairs of flexible struts 62 and 63. With such anarrangement, bearings or other interrelated movable parts are avoided atthe connection between the flexible struts and the movable frame in thevicinity of the plating bath thus avoiding deterioration of thesupporting structure from the corrosive environment of the plating bath.I

Movement for the movable supporting frame 61 and its associated trough18 is achieved through the action of two pairs of double acting pistonand cylinder arrangements 77 and 78 spaced apart so as to connect toeach end of movable frame 61. Only a single one of each pair is shown.Thus, by appropriate controls, as well known, pressure fluid is fed intofirst one end and then the other end of the pressure fluid actingcylinders to cause first a longitudinally and upwardly movement of themovable frame and its depending trough 18 and then an abrupt reversalback to the initial position. The various piston and cylinders arepivotally supported on frame supoorts 80 and 81. It should be understoodthat more than or less than two pairs of cylinders may be used,depending upon the load requirements and size of a particular trough.The action of the reversible piston and cylinder arrangements 77 and 78may be through pneumatic action or hydraulic action, as well known. Themovement of the double acting cylinders 77 and 78 may be achievedthrough a varietyof different control methods, as well known, in orderto provide appropriate time intervals between the upward action of thepistons and the lowering action of the pistons and for the requireddwell time required in electroplating.

the opposite end is rotatably supported in upright 124,-

with shaft 122 carrying cams 128 and 129, respectively, arrangedimmediately adjacent valves 126 and 127.

The construction and operation of valves 126 and 127 are the same exceptthat their associated cams are disposed differently on shaft 122 and maybe configured differently. Thus, only valve 127 will be discussed.

As can best be seen in FIG. 12, valve 127 receives compressed air asthrough port 130 from any well known source of compressed air, anddischarges air to one end of cylinders 77 and 78, it being understoodthat valve 126 controls-the opposite end of these cylinders. Thorugh theaction of valve 127 air is discharged through port 131 in a controlledmanner for the operation of cylinders 77 and 78.

For example, plunger 132 of valve 127 is moved through the action of camfollower as through linkage 134 supported for movement around pivot 138on support 133. As long as cam follower 135 is following surface 137 ofcam 129, either no air or continuous air is discharged through port 131.However, when cam follower 135 hits discontinuity 136 in surface 137,linkage 134 moves in a clockwise fashion around pivot 138,

and depresses plunger 132 of valve 127, which in turn operates valve127. Y

It should be understood that cams 128 and 129 are arranged on shaft 122and their surfaces configured so that they coordinate the action ofvalves 126 and 127 for operating cylinders 77 and 78 as desired in orderto provide appropriate dwell times and movement of trough conveyor 18.For example, if desired, a dwell period may be built into the cams usedon the cam shaft to control the valves in order to hold the movableframe and associated trough at the top of the stroke of the pistons. Thelower chambers of the cylinders may then be exhausted slightly beforeair is admitted to the upper chamber, as well known, in order to providemaximum downward and rearward acceleration of the supporting frame andassociated trough. The cam may also be provided with means on itssurface to permit immediate return of the trough to a dwell positionwith this dwell time permitting undisturbed contact of the work and thecathode electrode disposed along the floor of the trough. It is to beunderstood that cams of different configuration can be substituted inorder to provide a different sequence of operation for a particulardevice in accordance herewith, depending upon what operations are beingcarried on by the device. In addition, variations in the speed ofrotation of the cams can be made in order to vary the speed of thesequence of operations. For example, using a trough 2 feet wide and 12feet.

long, 2,000 pounds per hour of parts have been plated.

The dwell. was built into the cams for control of the of the supportingflexible members 62 and 63 m the for enhancing the movement andreorientation of the parts along the various levels of floor 60 of thetrough.

One form of trough floor 60 is perforated in order to enhance the entryof plating fluid into the trough and in and around the parts to beplated. These perforations are in the form of bores disposed throughoutthe trough floor. FIG. 6 is a section through two of these bores andshows the configuration of the bores for enhancing the utilization ofplating fluid flow for moving and tumbling parts on the trough floor 60.The upper part of bores 87 are smaller than the lower counter-bore 88.Generally, the upper and smaller bore 87 has a diameter onehalf that ofthe lower counter-bore. With a trough 12 vertical has an approximatelinear relationship with movement of parts through the trough. Verticalpositions produce maximum forward movement and little or no verticalmovement with no appreciable liquid circulation. By contrast, horizontalpositions produce no forwardmovement on a level trough but maximumvertical movement and liquid circulation. An angle of for disposition ofthe flexible struts 62 and 63 from the vertical is preferred forproducing optimum results.

If desired, the flexible supporting struts 62 and'63 may be used toincrease th downward and rearward velocity by locking the supportingcross shaft 73 in a position which establishes the desired spring force.Such an arrangement is shown in FIG. 8 in which the flexible strut 62 isarranged in the curve shown. A reverse configuration will augment upwardmovement.

With regard to the rigid support struts 20 disposed between movableframe 61 and the dependingtrough '18, these supports are angled,asshown, to be substanfeet long and 2 feet wide, and having 1 footsections at each level of trough floor 60, it has proved appropriate tohave distance designated 12 in FIG. 6 of 3/ 16 inch and distancedesignated c in FIG. 6 at V8 inch. With this size bore, satisfactoryresults have been achieved with about 400 perforations per square footin the trough floor. Further, the perforations and/or bores in thetrough floor 60 are inclined in the same manner as support 20 to helpmaintain the substantially concentric loading on the supports of thetrough and to held avoid and/or reduce stresses on the supportmountings.

One of the problems inherent in any electroplating environment is thefact that the plating bath liquid is deleterious to the parts associatedwith the equipment utilized for electroplating and also for any personwho happens to be within the environment of the electroplatingmechanism. For this reason, it is desirable and appropriate to avoidsplashing if at all possible of the liquid electroplating bath. TheApplicant here has succeeded in avoiding such splashing by theutilization of extensions 75 (FIGS.-4 and 5) depending from the sides ofthe trough along the entire length thereof. These extensions 75 serve todampen the hydraulic action which comes about when the trough is movingin a downward direction preventing a flow of liquid upwardly along thesides of the trough. Furthermore, these extensions 75 serve to enhanceor force liquid up through theperforations, described above, in thetrough floor. As further means for avoiding splashing of the liquid ofthe electroplating bath as the trough moves in the bath, it has beenfound that the upper level of the trough is placed below the liquidlevel surface 6fl at a distance withi n thei'angof between about 6inches and 10 inches, and preferably 8 inches.

" As can be seen in FIG. 4, anode trays 30 are disposed in a pluralityof sections above the level of the trough.

These anode trays 30 may obtain electrical connection from a series ofbus. bars extending across the tank,

such as 67 in FIG. 5. These anode trays can carry antially parallel tothe general direction of downward and rearward motion of the device forestablishing a substantially concentric loading onthe supports and forreducing stresses other than sheer. on the: support mountings.

* ured in order to take advantage of this hydraulic action odes of thedesired metal to be plated and in any desired configuration. It has beenfound convenient to use anodes in the form oF balls for easy handlingand replenishment. Electrical connections to the'electrodes are notshown, for clarity, since they form no part of this invention. Althoughthe trough floor may have various configurations for various purposesdepending upon that electroplating operations are to be carried out, ithas been found that the configuration shown in FIG. 7 provides enhancedresults. FIG. 7 isa section taken along lines 7-7 of FIG. 4 with thesupporting'parts for trough 18 removed for clarity. As is shown, eachsection and/or level of trough floor 60 has disposed therein a pluralityof spaced apart cathode electrodes 90 extending longitudinally along theentire length of the particular level. The rest of the floor of eachlevel is comprised of any appropriate non-conducting material such as,for example, polyvinyl chloride. The non-electrical conducting portionsof the trough floor are arranged in a series of longitudinally extendingpeaks 91 midway between each of the spaced apart electrodes 90. Theangle of the trough floor between peaks 91 and the adjacent electrodes90 is within the range of between about 6 and from the horizontal planeof the trough floor 60 and preferably 7.

With such an arrangement, the vwork pieces falling from one level toanother on trough floor 60 will be caused to tumble toward theelectrodes 90 as the work pieces move along the trough floor. Inaddition, because of this angle of Bclination providing tle-sles ofspaced apart peaks and valleys along each level of the trough floor,there is an enhanced reorienting action for the parts. This isparticularly helpful for small parts such as nuts and bolts which have atendency to collect in one part or section of the floor and cover eachother if they are not caused to continuously tumble and fall and movefrom one section to another during the operation, whether it beelectroplating, cleaning, rinsing, etc.

In certain instances, when the work pieces are very small, such as pins,for example, or of a configuration which would cause goblems ofcatching, etc with perforations 87 in trough floor 60, it is appropriateto have a solid trough floor having no perforations such as those shownin FIG. 6. However, with such an arrangement, it has been found thatfluid movement in certain portions of the trough tends to cause eddiesbecause of the natural static trough caused of liquid on the smoothsurface thus allowing certain parts to collect in one place and dwelltoo long in that place. In order to avoid this drawback, curvedoverhangs 97 and 98 (FIG. 10) are provided and extending over the edgesof the trough and along the entire length of each level thereof. Theseoverhangs cause, during descent of the trough, a forcing of the bathliquid up through spaces 99 between the trough sides and the overhangs97 and 98 in the direction of the arrows 100. This downwardmovement offluid into that portion of the troughcaused by the angle between thesides and the floor of the trough forces parts away from those sectionsof the trough where eddies would ordinarily occur. The same problemarises in the area immediately adjacent and and under the entry chute 50which introduces parts into the trough at the beginning thereof. Thus,overhang 94 (FIG. 9) is disposed along the entire width of the trough atthe entrance end thereof in order to produce liquid flow such as thatdesignated by arrows 95, thus causing work pieces entering the trough atthe entrance level to move forward-and toward the next level below.

It should be understood that the arrangement in accordance herewithprovides striking increases in the speed of movement of work piecesthrough the trough over any prior art devices. For example, using theelectroplating process in conjunction with apparatus, in accordanceherewith, and a solid trough floor, inch No. 10 type A round head screwswere zinc plated in 4 minutes, whereas in the past such plating wouldtake about 45 minutes. This speed is even more striking when the platedscrews were examined, as even the internal surfaces of the driving slotwere plated, an area notoriously difficult to plate.

In place of continuous conveyor 16, as shown and described in FIG. 1,conveyor 106 may be used which is, in effect, a trough configuredsubstantially the same as trough 18 only usually smaller in dimension.Trough conveyor 106 is inclined so that the various levels 83 thereofpresent a substantially stair step arrangement with the individual steps83 providing levels at which the work pieces are caused to jump from oneto the other. The trough 106 is suspended from two pairs of spaced apartflexible supports 108 similar to the flexible supports 62 and 63.However, in this case, the flexible supports are arranged to be undertension in the manner shown and described in FIG. 8. Thus, clamps 1'11hold their associated end of flexible supports 108 in a rigid manner inorder to provide the tension in 108. Clamps 1 11 are in turn rigidlyheld by supporting frame 113. A similar pair of flexible struts 108supports the lower or left hand end of conveyor 106 from frame 113. Thispair has been removed for clarity so as not to obstruct the relationbetween trough 18 and conveyor 106.

The entire surfaces of both the landing portions and the riserportionsof the individual steps 83 of conveyor 106 are foraminous to allow fluidin tank 10 to drain away from the work pieces moving up steps 83 throughand out of the fluid.

It has been found appropriate to arrange the individual steps 83 at adesired angle in order to enhance movement of work pieces along steps 83of conveyor 106. That is, the landing portions 138 of steps 83 areinclined counterclockwise within the range of between about .7-9 from aline perpendicular to the longitudinal axis of conveyor 106, andpreferably 7" Thus, angle d is within the range of between about 81 and85, and preferably 83, and angle e iswithin the range of between about3539, and preferably 37.

Conveyor 106 is caused to move through the action a work pieces arecaused to jump from one level 138 to another until they fall out ofchute 86 at the top of trough conveyor 106 where they may fall intofurther treating tanks or chutes leading into subsequent tanks forfurther treatment, rinsing, etc., all in well known fashion.

Control of piston and cylinder arrangement 84 may be pneumatic and/orhydraulic in the same fashion as piston and cylinder arrangements 77 and78. Preferably, it has been found that a pneumatic drive is appropriatewith a variable'speed electric motor driving a cam shAft for the valvingcontrol in the same manner as the drive for trough 18 described below.Th only difference is that the cycle for conveyor 106 is cammed to dwellat the bottom of the stroke, and thereafter to accelerate rapidly to thetop of the stroke. Following, there is a rapid deceleration by means ofrapidly ex- 1 1 hausting the lower portion of the cylinder chambers andadmitting air to the upper side before the stroke is comple'tgm all inwell known mannen'The combined action noted above causes the work piecesto move upwardly along thee various steps 83 of the trough conveyor 106,Preferably, an air cushion is incorporated into the air cylinders forthe bottom of their stroke. The angle a from the horizontal plane oftank for trough conveyor 106 is within the range of between about 30-45,and preferably 32.

Thus, as can be seen, arrangements are provided for electroplating largequantities of work pieces, particularly small parts, in a continuousrapid manner through the application of relatively inexpensive apparatusrequiring simple sources of power through the use of a new form ofmovement for the workpiece holding structure-in conjunction with novelbut uncomplicated configurations of apparatus utilizi ng the hydraulicforces broughtabout by that movement, and in a manner which makes theinvention, in accordance herewith, highly advantageous commercially.Furthermore, simple means are provided for changing the control of saidsupporting frame and with said flexible supports being connected undertension to counteract the and upwardly to transport articles in saidtrough for Y 'ward and upward of their initial position, and then thatmovementyas desired, to conform with the requirements of a particularelectroplating operation.

Other modifications and alternative implementations will now occur tothose versed in the art without departing from the spirit and true scopeof the inven-' tion. Accordingly, it is not intended to limit theinvention by what has been particularly shown and described.

I claim:

1. An exit conveyor trough for removing articles continuously out of acontainer and'having a longitudinally extending body portion ofchannel-shaped crosssection and a supporting frame, the combinationwhich comprises disposing said body portion at an angle of between aboutand 45 froma horizontal plane passing through the bottom of saidcontainer with the lowermost end of said body portion disposed in saidcontainer for receiving articles to be removed and with the uppermostend being disposed over the edge of said container for discharging saidarticles said body portion being supported from said supporting framefor movement through the plane of said angle by flexible supportsextending from the upper end thereof to said supporting frame with theends of said flexible supports being rigidly connected to said conveyortrough and abruptly in an opposite direction to rapidly return said bodyportion rearward and downward to its original position' to causemomentary suspension of the articles above the trough, and for holdingsaidtrough in its original position to permit inertial deposition of thesus pended articles onto said trough forward and upward of their initialposition.

2. Apparatus as recited in claim 1 in which said means for moving saidbody portion includes a source of pressure fluid, and a plurality ofpressure fluid actuated reversible double acting piston and cylindersconnected between said support frame and said trough conveyor forproviding the movement'thereof.

3. Apparatus as recited in claim 2 which includes a control disposedbetween said source and said fluid actuated piston and cylinders, saidcontrol comprising a pair of pressure fluid valves operable between anopen and closed position; a rotatable cam shaft extending along saidpair of valves, a pair of cams disposed on said cam shaft with each oneadjacent one of said valves, cam follower means disposed on said valvesand extending against the surface of said cams, and variable speed meansfor rotating said cam shaft for moving said valves from a closedposition to an open position and vice versa.

4. Apparatus as recited in claim 1 in which each of the landing portionsof said steps are disposed at an angle inclined counterclockwise withinthe range of between about 7-9 from a line perpendicular to thelongitudinal axis of said conveyor trough.

5. Apparatus as recited in claim 1 in which each of the riser portionsof said steps are disposed at an acute angle of within the range ofbetween about 35-39 from a plane drawn through the uppermost peaksformed by the intersections of said riser portions and said landingportions.

1. An exit conveyor trough for removing articles continuously out of acontainer and having a longitudinally extending body portion ofchannel-shaped cross-section and a supporting frame, the combinationwhich comprises disposing said body portion at an angle of between about30* and 45* from a horizontal plane passing through the bottom of saidcontainer with the lowermost end of said body portion disposed in saidcontainer for receiving articles to be removed and with the uppermostend beiNg disposed over the edge of said container for discharging saidarticles said body portion being supported from said supporting framefor movement through the plane of said angle by flexible supportsextending from the upper end thereof to said supporting frame with theends of said flexible supports being rigidly connected to said conveyortrough and said supporting frame and with said flexible supports beingconnected under tension to counteract the weight of said conveyortrough, a floor disposed in said body portion with the longitudinalsection thereof being configured in saw-toothed fashion to form a seriesof ascending steps, and means for cyclically moving said body portionrapidly in a first direction forward and upwardly to transport articlesin said trough forward and upward of their initial position, and thenabruptly in an opposite direction to rapidly return said body portionrearward and downward to its original position to cause momentarysuspension of the articles above the trough, and for holding said troughin its original position to permit inertial deposition of the suspendedarticles onto said trough forward and upward of their initial position.2. Apparatus as recited in claim 1 in which said means for moving saidbody portion includes a source of pressure fluid, and a plurality ofpressure fluid actuated reversible double acting piston and cylindersconnected between said support frame and said trough conveyor forproviding the movement thereof.
 3. Apparatus as recited in claim 2 whichincludes a control disposed between said source and said fluid actuatedpiston and cylinders, said control comprising a pair of pressure fluidvalves operable between an open and closed position; a rotatable camshaft extending along said pair of valves, a pair of cams disposed onsaid cam shaft with each one adjacent one of said valves, cam followermeans disposed on said valves and extending against the surface of saidcams, and variable speed means for rotating said cam shaft for movingsaid valveS from a closed position to an open position and vice versa.4. Apparatus as recited in claim 1 in which each of the landing portionsof said steps are disposed at an angle inclined counterclockwise withinthe range of between about 7*-9* from a line perpendicular to thelongitudinal axis of said conveyor trough.
 5. Apparatus as recited inclaim 1 in which each of the riser portions of said steps are disposedat an acute angle of within the range of between about 35*-39* from aplane drawn through the uppermost peaks formed by the intersections ofsaid riser portions and said landing portions.